J Hopman's Activities

Invalid parameter set for Hardening Soil with m = 1 and phi' < 20 degrees

J Hopman — Mon, 03 Jan 2022 13:26:54 GMT

Hello,

When using the Hardening Soil (or HS-ss) model I sometimes get an error when modelling soft or organic clays (see figure below) and Plaxis doesn't accept my parameter set.

After some trial and error I found out that it is the combination of the following parameters that causes most of the trouble: m = 1.0 in combination with a friction angle (phi') < 20 degrees.

I therefore have two questions regarding the modelling of a soft/organic clay with the hardening soil model:

Am I using realistic soil parameters for modelling a soft/organic clay?: From the Plaxis Material Models Manual I understand that for soft clays the power m should be taken equal to 1.0 (paragraph 6.1). I am therefore wondering if it is very uncommon to use a friction angle of < 20 degrees for a soft/organic clay when modelling in Plaxis? (other modelparameters I use are for example: yunsat/ysat = 15, E50 =4.000, Eoed = 2.000 , Eur = 24.000, c'ref = 0, K0-nc = 0,6744 (default))

If it is not uncommon to use m = 1 in combination with phi < 20 degrees: What would be the best way to model a soft/organic clay in a realistic way. The error message suggests that I should change the Eoed, E50, Eur or K0-nc parameters, but this does not make a lot sense to me because I have to increase or decrease the parameters a lot, which dramatically changes the stiffness behavior of the soil.

Thanks in advance for your help!

Printing Reached MSF(Safety Factor) using Python Scripting

Aryan Gupta — Thu, 11 Mar 2021 05:00:27 GMT

I have prepared python scripting code to calculate the safety factor using monte carlo simulations of different strength parameters. I want to know how can I can print the safety factor values (after each simulation has been completed) in excel format for all simulations that can help me understand the distrubution of safety factor values.

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Fri, 23 Jul 2021 03:20:18 GMT

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How can I create a UDSM material including parameters with python

J Hopman — Fri, 23 Jul 2021 07:49:43 GMT

Hello,

I would like to use Python to create a material from a User Defined Soil Model with the appropriate (soil) parameters.

So far I have been able to create the material, make sure the correct DLL file and Model in DLL are selected and define a few parameters.

However, I have not been able to define all of the required parameters.

In order to use the UDSM I need to define the parameters k0 and yt (among others) but I cannot find the names/descriptions of these parameters in the command line in Plaxis. When I change the value of the parameters in Plaxis I notice in the command line that they are stated somewhere in a very long string of numbers. But I don't know how I can process this in my python code in order to make sure the UDSM material is created with all the parameters that I would like to define.

I hope anyone can give me some suggestions to solve this problem.

Thanks in advance!

Jessy